Water Filtration and erosion control system and method

ABSTRACT

An erosion control system and method wherein a fabric filter bag is embedded with and/or filled with a flocculating polymer and is positioned on a sloping soil surface to dam and pond water flowing thereacross for settling of the particles in the water, and as the ponding water seeps into the bag the colloidal particles will be filtered or agglomerated for settling. The water then passes through and out of the bag and is further subjected to agglomeration and filtering by a skirt of filter material also impregnated with flocculating polymer, said skirt being anchored to the bag or stacked to maintain the position adjacent and downslope from the bag.

CROSS REFERENCE TO RELATED APPLICATION/CLAIM OF PRIORITY

This application is a divisional of U.S. patent application Ser. No.11/800,891, filed May 8, 2007, which claims priority under 35 USC §120from U.S. Provisional Application Ser. No. 60/831,835, filed Jul. 19,2006, entitled “Polymer Filtration System and Method for Erosion Controland Water Clarification”.

FIELD OF THE INVENTION

This invention relates to a system and method for capturing particles inrunoff water from sites undergoing grading, landscaping, miningmaintenance, logging, road building, land fills, utility and buildingconstruction, and other types of soil and environmental disturbances andfor controlling erosion at such sites. The erosion control method of theinvention is also useful for controlling flash flooding in flood proneareas, in areas subject to hazardous fires, in areas requiringindustrial waste management and in containing environmental spills andnuclear wastes. The invention particularly relates to a system andmethod employing filters, settling, and polymeric removal of solids andsuspended particles in the water run-on and runoff.

BACKGROUND OF THE INVENTION

In the development of subdivisions and shopping centers, in urbanexpansion, and in road and highway construction, huge quantities ofearth often must be either removed or disturbed leaving large areas ofexposed land without any cover or means to prevent erosion. Not only dogood environmental practices require erosion control but so do manylocal, state, and federal laws and regulations.

In addition to requiring control of the quantity and flow of water fromsites being developed, the quality of the water is also subject toregulatory requirements that grow more stringent each year. Thesestringent storm water regulations require more than conventional siltfencing products and straw bales. The Clean Water Act is changing theface of erosion control devices. Noncompliance with the NationalPollutions Discharge Elimination System, Phase II Storm WaterRegulations, implemented in 2005, is subject to administrative orders,civil actions, and/or criminal prosecutions on federal, state, countyand municipal government levels. All states review their erosion andsediment control manuals to reflect new information on best managementpractices, and many are requiring that erosion and sediment controlpractices meet a minimum performance standard. Most of the priorproducts do not provide compliance with the new act. As examples of afew of the many prior art processes and products for erosion controlreference is made to U.S. Patent Application Publication no.2004/0005198A1 and no. 2004/0133176A1.

Accordingly, an important object of the present invention is to providean erosion control and water clarification system and method that exceedthe new standards for storm water run-off.

Another object of the present invention is to provide compliant erosioncontrol and water clarification and filtration systems that can bequickly installed and removed, require limited site preparation orstaking, and are low maintenance during and after installation, andresult in improved water flow.

Another object of the present invention is to provide compliant erosioncontrol and water clarification products that are easily configured tothe landscape, contour, or lay out of the site and conform effectivelyto the soil, sand, rock, and paved surfaces at the site to providesuperior soil confinement with minimal land disturbing activity.However, the invention may also be used where there has been no landdisturbance and it is desirable to control surface water flow.

Still another object of the present invention is to provide an effectiveerosion control method and means that can be readily used in a widevariety of applications.

SUMMARY OF THE INVENTION

The above objectives are accomplished according to the present inventionwhich removes unwanted contaminants from run-off water and in one aspectsequentially employs the steps of settling, filtering, and agglomeratingparticulate matter in run-off water. In one aspect this is accomplishedby providing an erosion control system comprising a plurality ofelongated, closed filter bags constructed from a filtration fabric. Thebags act as a dam to pool water for settling and, as water seeps throughthe bags, the bags also act as a filter to remove soil particles. Apolymeric material is preferably disposed within the filter bag foragglomerating colloidally suspended particles in water passing throughthe bag wall from the dammed up pool whereby the agglomerated particlessettle within the filter bag and remain.

In another aspect, after passing through a filter bag the waterencounters a skirt or apron of filter material that is also impregnatedwith an agglomerating polymer to further group suspended particlestogether so that they will settle out. The skirt is positioned downslope from the bag and may be attached to the bag for stable positioningas the terrain dictates.

In yet another aspect the present invention employs a polymer systemthat includes a special formulation of a blended water-soluble anionicpolyacrylamide dry powder product referred to hereinafter as “PAM” thatis used to minimize soil erosion caused by water and wind. There areother flocculants or agglomeration promoters that are known and havebeen used in water treatment for a long number of years. Alum, gypsumand chitosan have been used but PAM has been found especially useful inerosion control. PAM decreases soil sealing by binding soil particles,especially clays, to hold them on site. In addition, these types ofproducts may also be used as a water treatment additive to removesuspended particles from runoff. This system is designed as a moreeffective replacement of prior art velocity dissipating devices such asthe conventional siltation fence product, baffle units, and other tubetype products currently in use today.

Water clarity is achieved primarily by particle reduction or removal,that is, by removing the suspended particulate matter. Particulatematter which can be removed by normal gravitational settling isclassified as a settleable solid. These solids are removed by reducingthe velocity of the water to a “ponding” state that will allow settlingto take place. The filter bag units act first as a dam to create a pondor pool by retarding the flow of water and sediment thereby allowingtime for sedimentation of suspended particles. This takes place on theinfluent side of the bag and is a first step in the process of theinvention. The present invention provides a unique combination of threewater treatment phases of settling, agglomeration, and filtering. In oneaspect, the bag of the present invention can perform all three phases.Agglomeration and filtering may be looked at as methods of “capturing”unwanted particles.

The suspended particulate matter which does not settle during theponding phase from gravitational settling or is not removed by thefiltering effect of the bag wall material is considered to be colloidal.Colloidal particles maintain a negative ionic charge and do not haveenough mass to settle. These are the particulates that cause the waterto appear turbid or opaque. The effective removal of these colloids canbe greatly enhanced through the introduction of a polymeric agent to theturbid water. These agents collectively bond naturally suspendedparticles together causing them to gain sufficient weight to settle outof suspension through gravitational sedimentation. The preferred agent,PAM, is placed within a filter bag in powder form without mixing or itmay be mixed with the ballast. Water flow through the bag is relativelyslow giving the agglomerated particles time to settle. In the bag, wateris absorbed into or is trapped in the ballast if the ballast comprisesmaterials that tend to absorb water such as mulch, wood chips, saw dust,cotton seed hulls, pecan shells and/or other natural, organic, vegetablematerials. In addition, the ballast may comprise synthetic material suchas synthetic foam shavings, synthetic fibers such as shredded polyestercord reclaimed from rubber tires, or ground rubber, and compriseinorganic materials such as gravel or crushed stone. The ballastpreferably is a combination of the synthetic and organic materials. Thewater trapped within the ballast greatly increases the bag weight andits stability on a slope.

Soil types can vary greatly depending on variables such as type of clay,humus, and soil pH. Due to these variations, on-site soil testing andevaluation is a recommended procedure. For example, the site may be onewhere coal slurries, mine trailings, or waste petroleum products arepresent. The soil test will determine the correct dosage amount andpolymer system to be recommended and selected. By ensuring the correctdose and type of polymer, greater water clarity can be achieved througha prescribed formulation.

Water that passes through the bag may still contain colloidal particles.In a preferred embodiment, as this water leaves the bag it contacts themesh skirt that is impregnated with PAM to induce further agglomerationof the suspended particles. The mesh may be jute, cotton, or othersuitable organic or inorganic material. In addition to exposing the runoff water to the PAM, the skirt also retards water flow and is a backupto restrain and prevent any breakthrough of higher velocity waterstreams in a heavy downpour. As the particles settle they may settledirectly on the surface soil. These sediments tend to increaseflocculation thus increasing the pore volume of the soil which reducesthe quantity of water run-off while increasing its quality. For furthererosion control, grass or other ground cover seed can be attached to theskirt. Also, additional skirts may be provided downslope to ensure ahigh level of erosion control. In one aspect, a skirt in and by itselfmay perform the erosion control functions of agglomerating andfiltering. Skirts may be placed on steep inclines and used as ditchliners.

In another aspect, the ballast which is disposed within the filter bagwith the polymeric material to filter water passing through, restrainsmovement of the filter bag when placed on a surface across which watermay flow. The ballast enables the filter bag to remain where positionedand effectively dam water flow for a time sufficient to promote settlingas well as filtering the water passing through the bag.

Preferably, the ballast filter material may comprise the materialsmentioned above and the fabric, preferably, a polymeric material, may bea woven polypropylene, and the polymeric material may comprise a watersoluble anionic polyacrylamide (PAM).

Advantageously, the filter bag is in the shape of a tube with closedends wherein the diameter of the tubular filter bag is in the range fromabout 8″ to about 12″. The bags are marketed under the trademark“EROSION EEL”™ owned by Denny Hastings FLP14, a family Limited LiabilityCompany of Nevada. A tube shape is one very useful configuration but thebag may also be multi-sided or gusseted. The filter bags are stackable;one upon another, and/or the fabric preferably comprises a non-toxic,flame retardant polymeric material. A UV inhibitor as well as a flameretardant is included in the skirt and bag material.

In another aspect of the invention, a method of controlling erosion isprovided comprising the steps of forming elongated filter bags fromwoven fabric having weave openings of a size that will filter thesediment from the water passing through the fabric openings and at leastpartially filling the filter bag with a ballast material that alsofilters the water. The method comprises disposing an agent within thefilter bag for agglomerating colloidal particles suspended in waterpassing through the filter bag and closing the filter bag to enclose theballast and the agglomerating material. The filter bags, when positionedon a surface with a skirt, control the flow of water across the surface.Advantageously, the ballast material is selected as mentioned above toprovide sufficient weight for stabilizing the movement of a filter bagon the surface upon which it is placed. The fabric of the bag maycomprise a sealable material and the filter bag may be formed and closedin a form-fill-seal process. A pre-formed bag may be filled on site bygravity feed, or by mechanical means such as by pumping or blowing theballast into the bag on site. While on-site filling is possible it hasproven to be impractical, because the ballast does not blow or pumpreadily without clogging as a bag is filled and it is inconvenient tomix ballast on site. A preferred method is described below.

The fabric of the filter bags has uniform openings to provide a constantlevel of filtration and sediment control over the life of the productand to provide handling of higher flow rates while being easily cleanedif needed. The filter bag units and skirts may be easily transported ormoved temporarily for ingress or egress activity, or for installation onthe most difficult to reach job sites. Through installation designs andthe ability to stack the filter bag units, a multitude of erosioncontrol designs can be achieved. Bags can be rotated and cleaned by rainwater or removed and mechanically cleaned on or off site. The skirtwhich is attached underneath or to the down hill side of the bag is laidparallel to the bag. It may comprise the same material as the bag or maybe jute or cotton mesh impregnated with PAM or other agglomeratingagent.

In a further aspect, the invention is a method of making the elongatedfilter bag comprising the steps of mixing predetermined quantities of 1)organic materials which may include, for example, hardwood chips, straw,cocoa shells, ground corn cobs or cotton seed hulls; 2) recycledshredded rubber or foam rubber shavings or from tires; 3) synthetic,organic, or mineral fibers which may include carpet shavings; and 4) achemical agglomerating agent to form a filler mixture. These steps arepreferably performed with the assistance of a conveyor. The mixture isagitated so that it flows freely, and is then deposited by gravity intovertically positioned, fabric tubular-shaped bag with one open end, andthen the tubes or bags are closed and removed after filling. The filledbags are now ready for positioning for erosion control.

In a still further aspect, the bags may be equipped with RFID tags,i.e., radio frequency, identification devices making required periodicinspection of sites easier and more complete. The RFID device may recordeach time an inspector with a transmitting and recording device of theappropriate range and frequency has been at the site to make aninspection. Likewise, the inspector will be able to tell if all bagsremain at the site and are intact. Reports may be readily generated inthis manner. Also the length of time a bag has been installed can bemonitored since, at present, 24 months is the projected effectivelifetime of a bag.

In yet one additional aspect, the present invention is a method ofcontrolling erosion on a sloping surface having soil susceptible toerosion comprising the steps of providing a filtering fabric with anagglomerating or flocculating polymer embedded therein; forming a shapedarticle from said fabric, and securing said article to said slopedsurface. The article may be a bag or tube or skirt and the means forsecuring the article may be ballast in the case of a bag or attachingthe skirt to another article or by staking it. The skirt may also be areceptacle that, when essentially flat, may be filled with ballast. Thearticle may also be secured by its own weight and the adhesiveproperties that develop with the contact of the polymer with the soil.

DESCRIPTION OF THE DRAWINGS

The construction designed to carry out the invention will hereinafter bedescribed, together with other features thereof.

The invention will be more readily understood from a reading of thefollowing specification and by reference to the accompanying drawingsforming a part thereof, wherein an example of the invention is shown andwherein:

FIG. 1 is a front perspective view illustrating a polymer filtrationsystem and method for erosion control and water clarification at aconstruction site according to the present invention;

FIG. 2A is a filter bag of a polymer filtration system and methodaccording to the invention;

FIG. 2B is a plurality of filter bags stacked to provide greater erosioncontrol in a polymer filtration system and method according to theinvention;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2A;

FIG. 4 is a sectional view similar to FIG. 3 illustrating an alternateembodiment of a filter bag according to the invention;

FIG. 5A is a sectional view taken along line 5-5 of FIG. 2B;

FIG. 5B is the view if FIG. 5A with a portion of the skirt of thepresent invention wrapped around the stack of bags;

FIG. 6A is a view illustrating an application of a filter bag accordingto the invention for protecting a street and curb drain;

FIG. 6B is a schematic illustration of another application of theinvention for channeling and ponding, and filtering water according tothe invention;

FIG. 7A is a side view of a schematic representation of equipmentarranged to load filter bags of the present invention;

FIG. 7B is the top view of the equipment layout of FIG. 7B;

FIG. 8 is a perspective view illustrating a polymer filtration systemand method for erosion control and water clarification according to theinvention wherein a water clarification skirt impregnated with a polymermaterial is added to the filter bag for agglomeration and precipitationof particulate matter is the water stream;

FIG. 9A is a representation of an elevation section of the view of FIG.8 showing Phase I, Phase II, and Phase III of a system and methodaccording to the invention for erosion control and water clarification;

FIG. 9B is the representation of FIG. 9A wherein the skirt of thepresent invention is wrapped partially around the bag for furtherstability on a sloped surface; and

FIGS. 10A, 10B, and 10C are sectional views taken along lines 10A-10A,10B-10B, and 10C-10C of FIG. 8 illustrating the agglomeration processtaking place at the filter skirt.

DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now in more detail to the drawings, the invention will bedescribed in more detail.

FIG. 1 illustrates a simple job site of a residential home 10 having adownward slopping lot 12 which is provided with an erosion control andwater clarification system, designated generally as A, employing anarrangement of filter bags, designated generally as B. The front row offilter bags B includes water clarification skirts C. The same may alsobe provided on the side row of filter bags, if desired. As can best beseen in FIG. 2A, filter bag B includes a filter fabric 14 formed into anelongated, tubular filter bag B. For example the bag tube may be formedwith a longitudinal seal, or two side seams and the seams may be sewn,thermal or adhesively bonded, and the like. In some instance, a seamlesswoven tube may be used. One end of the bag, 14 a is closed and the otherend of the bag 14 b may be opened for filling and then closed by anysuitable means. The bag may be provided with a plurality of straps 16,or other means so that the bag may be handled for installation,movement, and removal. While filter bag B may have many designsdepending on the desired application, the filter bag is preferably inthe range of 3 to 20 feet with 3 to 12 feet being most preferred. In thepreferred embodiment, the filter bag may be provided with four handlestraps 16 that allow it to be easily moved. Filter bags can range from 4inches to 20 inches in diameter, with a preferred diameter being in therange of 8 to 12 inches. In the preferred range of length and diameter,the filter bag will weigh less than 125 pounds when dry with optimumweight being in the range of 100 to 125 pounds when dry. The fabric 14has openings 14 a of a size that passes water but filters out settleablesolids 66 (FIG. 9). FIG. 2B illustrates the stacking of three or morefilter bags to provide increased erosion control and waterclarification. The ballast material may be an organic material such asmulch, wood chips, crushed stone, saw dust, cotton seed hulls, pecanshells or an inorganic material such as ground rubber, or synthetic foamshavings and/or any other suitable materials or combination ofmaterials. The most suitable mulch material would be a first grindhardwood chips having mulch pieces of three quarter inch to two inchesmeeting AASHTO (American Association of State Highway and TransportationOfficials) certification for use on unvegetated filter barrierinstallation. In a preferred embodiment a rubber ballast is utilizedwherein the rubber pieces are in the range of one eighth to two incheswith less than three quarter inches being preferred. The filter fabricmay be woven, knitted, or non-woven. If woven, the filter fabric may bewoven flat or tubular. The weave pattern may be double twisted twill,square weave, or plain. Knitted fabric may be knitted circular, flat, orwith a weft insertion. Non-woven fabric may be needle punched, wet laid,spun bond, spun laced, or melt blown. Stitch bonded fabric, laminated,or a fabric combination utilizing two or more of the technologies may beused. Preferably, the fabric material is a polymer such as polyester,nylon, polyolefin, or organic fibers such as jute, cellulose, etc. Otherparameters of fabric 14 and filter bag B are shown below.

Typical Values Design Range Mechanical Properties Test Method Units MDCMD MD CMD Grab Tensile ASTM D4632 lbs. 400 250 50-600 25-600 Grabtensile Elongation ASTM D4632 % 15 6  0-50  0-50 Trapezoid Tear StrengthASTM D 4533 lbs. 170 110 50⁺ 30⁺ Mullen Burst Strength ASTM D 3786 psi800 200⁺ min. Puncture Strength ASTM D 4833 lbs. 180  60⁺ min. Flow RateASTM D 4491 gal/min/ft² 40 20-80 Permeability ASTM D 4491 cm/sec 0.050.05 +/− 33% Permittivity ASTM D 4491 sec-1 0.52 0.05 +/− 33% ApparentOpening Size ASTM D 4751 mm/US mm US SIEVE mm 0.300- US SIEVE (AOS)Sieve 0.600 (30) 0.850 20-50 UV Resistance (500 ASTM D 4355 % 70 50⁺hours) Strength retained Flame Resistance GRADE YES “E” Ounce Weightoz/sy 8.0  2-20

As can best be seen in FIGS. 3-5B, filter bag B includes a ballastmaterial 18 to provide the filter bag with sufficient bulk and weight toassist in maintaining the filter bag in place. In this embodiment PAMmay be uniformly distributed in the ballast material. FIG. 4 shows analternate embodiment wherein anionic polyacramide material at 20 isadded to the bottom of the filter bag for removing suspended particlesin the water to clarify and filter the runoff in a manner to be morefully described hereinafter. The effect of the reaction of the PAM andthe soil is that the skirt and the bag will be chemically bonded to theground.

The composition of ballast 18 is preferably selected for the majorcontaminant to be removed. For removal of suspended soil particle orcoal in coal slurries a mixture of approximately equal parts on a volumebasis of inorganic, organic and synthetic material is preferred.Virtually 100% synthetic material is desirable where absorption ofcontaminant particles may be desired e.g. chemical contaminant, minetrailings etc. may require different ratios and materials depending onthe contaminant. Thus, selection of the ballast composition willpreferably be matched to the contaminant to be removed.

FIG. 5A is a sectional view taken along line 5-5 of FIG. 2B where threeof the filter bags are arranged in a stacked configuration for greatererosion control protection. According to the invention, soil andsedimentation 22 backs up behind the filter bags as the filter fabricslows and allows the water to flow through the ballast material in thebag.

It will be noted in FIG. 5A that the ballast and PAM treated fabricallows the filter bag to adhere flat and close to the ground so thatonly a minimal amount of water is diverted underneath the filter bag.The drape also allows the stacked bags to fill in between each othereffectively. Of course any number of the filter bags can be stackeddepending upon the need and application being made. FIG. 5B illustratesan alternate embodiment wherein a skirt is attached at the strap or loopon the top of the uppermost bag and is wrapped around the left side ofthe stack of bags and continues under the bags to the lower right side.This “wrap” serves to stabilize the stacked bags and the skirt.

FIGS. 6A and 6B show two examples of arrangements and systems of thepresent invention. FIG. 6A illustrates a filter bag surrounding a roadcurb drain wherein a filter bag B of sufficient length is placed tosurround the drain to prevent the flow of sediment and other undesirableparticles into the drain. FIG. 6B illustrates the versatility of thefilter bags in an erosion control system wherein the plurality of filterbags B of different lengths are arranged to first channel the flow ofwater at 24 into a ponding area 28 formed by bag 28 wherein the water isallowed to form a pond where the settleable solids settle out of thewater. As will be described in more detail, the filter fabric slows theflow of water effectively to form the pond and allow the solids tosettle out as the water filters through the filter fabric and ballastbefore being disbursed by a final filter bag 34 and/or clarificationskirt C may be provided on the down stream side of each filter bag asneeded.

As can best be seen in FIGS. 7A and 7B, a process for preparing erosioncontrol bags is illustrated wherein a special blend of water-solubleanionic polyacrylamide (PAM) dry powder agent is blended with theballast materials to form the mixture to fill filter bag B. The fillingis best done in a production line setting where the mixing ofingredients can be thoroughly accomplished and the mixture is agitatedso that it is flowable by gravity feed through a chute into a bag ratherthan being blown or sprayed into a bag. The process shown in FIGS. 7Aand 7B and described in this paragraph and in the two paragraphs belowis the best mode for making the filled bags of EROSION EEL™ product ofthe present invention.

Referring to FIGS. 7A and 7B together, raw materials are placed intoeach of four holding bins as follows: Hopper 80 holds organic hardwoodchips, straw, cocoa shells, ground corn cobs, or cotton seed hulls;hopper 81 holds recycled shredded rubber; hopper 82, also identified asa “Bale Processing Unit” holds synthetic or organic fibers, and hopper83, also identified as the “Chemical Hopper” holds a chemical powderpreferably PAM and/or any other chemical additives that might bedesirable.

Specified amounts by volume of wood chips, shredded rubber, syntheticrecycled carpet fibers, straw, cocoa shells, ground corn cobs, or cottonseed hulls are deposited in pre-set amounts from hopper 80 onto thecontinuously moving mixing conveyor 85. As the mixing conveyor movesunder hopper 81 a pre-set amount of shredded rubber is deposited onto ofthe ingredients previously deposited from hopper 80. As the mixingconveyor moves under the bale processing unit 82, synthetic carpetfibers, if included in the mix, are deposited in a pre-set amount on topof the previously deposited ingredients. As the ingredients from hopper80, hopper 81, and the bale processing unit 82 move under the chemicalhopper 83, a pre-set amount of PAM is deposited onto the previouslydeposited ingredients. From chemical hopper 83 the combined rawmaterials are thoroughly mixed in the mixing conveyor 85. As the mixedfiller ingredients leave the mixing conveyor 85, they are deposited bygravity onto incline conveyor 86 which transports them into bagging unithopper 87. Ingredients are agitated by the settling device 89 and flowfreely into the geo-textile tube attached at the bottom of bagging unithopper 87. Dust controller 88 reduces and collects particles that aremade airborne by the process. Filled bags are manually released from thebagging unit, are manually tied and dropped to the bagging facilityfloor.

FIG. 8 illustrates another embodiment of treating the filtered waterwith PAM to agglomerate and precipitate colloidal particles out of thewater. As can best be seen in FIG. 8, filter bag B includes a downstream water clarification skirt C fixed to the bag in any suitablemanner such as links 50 connected to straps 16 of the bag. A stiffenerstrip 52 which extends the length of the skirt is connected to the linksand tends to hold this side of the skirt flat against the ground.Preferably the length of the filter bag and the length of the skirt aregenerally the same. The width of the skirt may be any suitable widthsuch as one, two, or three feet, or other widths depending on theapplication being made. The skirt is preferably formed of an organicmaterial such as jute, cellulose, or the like. The skirt may be woven,non-woven, or knitted. Most importantly, the skirt is embedded,impregnated, coated, lightly adhered with, or otherwise provided withPAM. Preferably, the PAM agent is not too securely embedded in the skirtmaterial so that it can be contacted by the water that flows thoroughthe skirt to agglomerate with the colloidal particles which will settleout on the site. In one aspect, grass seed may be included in the skirt.This process can best be seen in FIGS. 10A, 10B and 10C. FIG. 10Aillustrates how the PAM agent D is carried in and on the fabric 54 ofskirt C. The fabric may be multilayer with the PAM agent sandwichedbetween layers or the surface of the fabric coated with a water solubleadhesive to adhere PAM thereto initially. FIG. 10B illustrates theagglomeration step wherein the suspended colloidal particles in thewater are agglomerated to form agglomerated particles, generallydesignated as 60. Eventually, the agglomerated particles separate andleave remaining PAM agent D while the agglomerated particles soak intothe ground. While it is preferred that the skirt be attached to the bagfor secure anchorage and positioning, the skirt could be staked inposition. However, the skirt alone without attachment can be staked inposition. In any event, it is important that the position of the skirtbelow and in close proximity to the bag be maintained.

FIG. 9A illustrates the system as a 3-phase or three step method forcontrolling erosion and clarifying storm water run-off. The first phase,Phase I, is a ponding phase that occurs upstream of filter bag B. Inthis phase, the water and sediment flow is slowed to a “ponding” stateby the damming effect of bag B that allows settling of those solids 66which can and will settle out of water pond 68 into the ground. Inaddition, the particles that are too large to pass through the materialof bag B will be “filtered out” before entering the bag. The secondphase, Phase II, is the filter and agglomeration phase. In this phasethe matter 70 which does not settle during the ponding phase isconsidered to be colloidal, and is agglomerated through the introductionof the PAM agent in the interior of filter bag B. The anionic colloidalparticulate matter is agglomerated by the presence of anionic PAM. Whenenough agglomeration occurs the agglomerated masses 72 become heavyenough to settle out the bag or be trapped by the filter fabric. Thethird phase, Phase III, is an agglomeration phase wherein the particles74 which do not agglomerate in Phase II encounter the waterclarification skirt as described above. In this phase, particles 74encounter PAM agent D carried by skirt C, which acts like a blanket ofPAM, and are caused to agglomerate through and under the skirt until themasses 60 soak into the ground. Thus, in addition to providing anagglomeration medium, the skirt tends to further retard the velocity ofthe water and check any flow streams that may have developed around orunder the bag. A high degree of water clarity is achieved for the waterrunoff with the end result of a higher effluent quality which is safe toflow into streams and rivers. The settled particle or “floc” improvesoil quality and tend to further reduce storm water run off.

FIG. 5B as mentioned above and FIG. 9B show a method and configurationfor stabilizing a bag and skirt on a sloping surface by partiallywrapping the skirt around the bag. This configuration keeps the skirtsecurely in place and adds a layer of agglomerating and filteringmaterial to the system where the water flow is greatest.

The best mode of the invention which, in one aspect, is the completeerosion control system including the selection of the appropriateballast mix, making the filter bags and properly placing them on asloping surface that is subject to erosion. The best mode process formaking the erosion control bag product has been described above inconnection with FIGS. 7A and 7B. The best mode construction of a filterbag is shown in FIGS. 2 and 3 where the bag is a twill weavepolypropylene with UV inhibitor and flame retardants having a 9½″diameter with the bag interior charged with PAM in the range of 20 to200 gms per bag with the preferred charge being 20 to 30 gms/bag. Ingeneral, the concentration of PAM will conform to local, state andFederal guidelines and regulations for its use. The fabric is in therange of 3 to 16 oz/yd with sieve size from No. 10 to No. 100. Theballast is filled with, by equal volume, chopped nylon fibers, choppedtire rubber, and mulch. The best mode bag length is about 116″ with afilled bag weighing in the range of 120 to 125 pounds. It should beunderstood that the bags and ballast are site specific and will betailored according to each location.

While a preferred embodiment of the invention has been described usingspecific terms, such description is for illustrative purposes only, andit is to be understood that changes and variations may be made withoutdeparting from the spirit or scope of the following claims.

1-28. (canceled)
 29. A method of controlling erosion on a surface havingsoil susceptible to erosion comprising the steps of providing afiltering fabric with an embedded flocculant therein; forming a shapedarticle from said fabric; and, positioning said article on said surface.30. The method of claim 29 wherein the shaped article is a bag and themethod of securing said article comprises filling the bag with ballastmaterial.
 31. The method of claim 29 wherein the shaped article is askirt and the method of securing is performed by attaching the skirt toanother article or staking said skirt.
 32. The method of claim 29wherein said article is secured by its own weight in combination withthe adhering properties of said flocculant. 33-34. (canceled)
 35. Themethod of claim 29 wherein said surface is a sloping surface and saidfilter fabric is a multilayer fabric.
 36. The method of claim 32 whereinthe shaped article is a flattened bag.
 37. The method of claim 36wherein said flattened bag has ballast therein.
 38. The method of claim32 wherein the shaped article is a skirt.
 39. The method of claim 32wherein the flocculant material has been selected in accordance with thetype of said soil.
 40. A shaped article for controlling erosion on asurface having soil susceptible to erosion comprising: a) a filteringfabric; and b) a flocculant embedded therein.
 41. The shaped article ofclaim 40 wherein said filter fabric is a biodegradable material.
 42. Theshaped article of claim 40 wherein said flocculant is selected inaccordance with the type of soil in the surface upon which the articlewill be positioned.
 43. The shaped article of claim 40 wherein saidarticle is selected from the group of shaped articles consisting ofbags, tubes, and skirts.